In-plane crashworthiness study of bio-inspired metallic lattice structure based on deep-sea glass sponge

Inspired by the double-diagonal reinforced configuration of deep-sea glass sponges, a metallic bio-inspired lattice structure (BLS) was fabricated using additive manufacturing (AM) techniques. In-plane quasi-static compression tests demonstrated the energy absorption (EA) of BLS was improved by about 60 % compared to conventional lattice designs. Subsequent experimental and numerical investigations examined the effects of wall thickness, elucidating the corresponding variations in crashworthiness indicators. The study revealed that when the wall thickness increased from 0.40 mm to 0.60 mm, the EA and mean crushing force (P_m) exhibited a substantial increment of 58.1 % and 91.1 %, respectively. The finite element (FE) simulations underwent experimental validation, exhibiting satisfactory agreement. Parametric studies using the validated FE model explored the effects of geometric factors, such as diagonal distance, unit size, unit number and graded thickness on the crushing performance of BLS. Results indicated that enhancing the EA performance of BLS was achievable by concurrently reducing the unit size and increasing the unit number. The maximum EA achieved was 3535.5 J, representing a 62.9 % improvement compared to the initial configuration, which exhibited an EA of 2170.7 J. Additionally, the introduction of graded thickness facilitated a controllable collapse pattern, thereby improving the crashworthiness performance. Lastly, the in-plane dynamic crushing simulations were conducted, identifying three distinct collapse patterns, where the U-Mode exhibiting a negative Poisson's ratio (NPR) behavior. A deformation mode map and rigid-perfectly plastic-lock (R-PP-L) model were developed to evaluate the dynamic response of BLS under varying relative density (RD) and impact velocity (V). These findings provided valuable insights for designing sponge-inspired structures with enhanced crashworthiness performance.